2,233 research outputs found
A preliminary study of genetic factors that influence susceptibility to bovine tuberculosis in the British cattle herd
Associations between specific host genes and susceptibility to Mycobacterial infections such as tuberculosis have been reported in several species. Bovine tuberculosis (bTB) impacts greatly the UK cattle industry, yet genetic predispositions have yet to be identified. We therefore used a candidate gene approach to study 384 cattle of which 160 had reacted positively to an antigenic skin test (‘reactors’). Our approach was unusual in that it used microsatellite markers, embraced high breed diversity and focused particularly on detecting genes showing heterozygote advantage, a mode of action often overlooked in SNP-based studies. A panel of neutral markers was used to control for population substructure and using a general linear model-based approach we were also able to control for age. We found that substructure was surprisingly weak and identified two genomic regions that were strongly associated with reactor status, identified by markers INRA111 and BMS2753. In general the strength of association detected tended to vary depending on whether age was included in the model. At INRA111 a single genotype appears strongly protective with an overall odds ratio of 2.2, the effect being consistent across nine diverse breeds. Our results suggest that breeding strategies could be devised that would appreciably increase genetic resistance of cattle to bTB (strictly, reduce the frequency of incidence of reactors) with implications for the current debate concerning badger-culling
Acanthamoeba keratitis: confirmation of the UK outbreak and a prospective case control study identifying contributing risk factors
BACKGROUND/AIMS: Acanthamoeba keratitis (AK) is a chronic debilitating corneal infection principally affecting contact lens (CL) users. Studies were designed to test claims that the UK incidence may have increased in 2012–2014 and to evaluate potential causes.
METHODS: Annualised incidence data were collected from January 1984 to December 2016. Case-control study subjects were recruited between 14 April 2011 and 05 June 2017. Reusable CL users with AK were recruited retrospectively and prospectively. Controls were reusable CL users, recruited prospectively, with any disorder other than AK. Multivariable analysis of questionnaire data measured independent risk factors for AK.
RESULTS: The current outbreak of AK started in 2010–2011 with an incidence threefold higher than in 2004–2009. Risk factors for AK were: Oxipol disinfection, CLs made of group IV CL materials, poor CL hygiene, deficient hand hygiene, use of CLs while swimming or bathing, being white British, and for those in social classes 4–9.
CONCLUSION: AK is a largely preventable disease. The current outbreak is unlikely to be due to any one of the identified risk factors in isolation. Improving CL and hand hygiene, avoiding CLs contamination with water and use of effective CL disinfection solutions, or daily disposable CLs, will reduce the incidence of AK. In the longer-term, water avoidance publicity for CL users can be expected to reduce the incidence further. Ongoing surveillance of AK numbers will identify changes in incidence earlier. Evaluation of Acanthamoeba contamination in end-user drinking water would contribute to our understanding of regional variations in the risk of exposure
Tunable magnetic exchange interactions in manganese-doped inverted core/shell ZnSe/CdSe nanocrystals
Magnetic doping of semiconductor nanostructures is actively pursued for
applications in magnetic memory and spin-based electronics. Central to these
efforts is a drive to control the interaction strength between carriers
(electrons and holes) and the embedded magnetic atoms. In this respect,
colloidal nanocrystal heterostructures provide great flexibility via
growth-controlled `engineering' of electron and hole wavefunctions within
individual nanocrystals. Here we demonstrate a widely tunable magnetic sp-d
exchange interaction between electron-hole excitations (excitons) and
paramagnetic manganese ions using `inverted' core-shell nanocrystals composed
of Mn-doped ZnSe cores overcoated with undoped shells of narrower-gap CdSe.
Magnetic circular dichroism studies reveal giant Zeeman spin splittings of the
band-edge exciton that, surprisingly, are tunable in both magnitude and sign.
Effective exciton g-factors are controllably tuned from -200 to +30 solely by
increasing the CdSe shell thickness, demonstrating that strong quantum
confinement and wavefunction engineering in heterostructured nanocrystal
materials can be utilized to manipulate carrier-Mn wavefunction overlap and the
sp-d exchange parameters themselves.Comment: To appear in Nature Materials; 18 pages, 4 figures + Supp. Inf
From presence to consciousness through virtual reality
Immersive virtual environments can break the deep, everyday connection between where our senses tell us we are and where we are actually located and whom we are with. The concept of 'presence' refers to the phenomenon of behaving and feeling as if we are in the virtual world created by computer displays. In this article, we argue that presence is worthy of study by neuroscientists, and that it might aid the study of perception and consciousness
Lepton Acceleration in Pulsar Wind Nebulae
Pulsar Wind Nebulae (PWNe) act as calorimeters for the relativistic pair
winds emanating from within the pulsar light cylinder. Their radiative
dissipation in various wavebands is significantly different from that of their
pulsar central engines: the broadband spectra of PWNe possess characteristics
distinct from those of pulsars, thereby demanding a site of lepton acceleration
remote from the pulsar magnetosphere. A principal candidate for this locale is
the pulsar wind termination shock, a putatively highly-oblique,
ultra-relativistic MHD discontinuity. This paper summarizes key characteristics
of relativistic shock acceleration germane to PWNe, using predominantly Monte
Carlo simulation techniques that compare well with semi-analytic solutions of
the diffusion-convection equation. The array of potential spectral indices for
the pair distribution function is explored, defining how these depend
critically on the parameters of the turbulent plasma in the shock environs.
Injection efficiencies into the acceleration process are also addressed.
Informative constraints on the frequency of particle scattering and the level
of field turbulence are identified using the multiwavelength observations of
selected PWNe. These suggest that the termination shock can be comfortably
invoked as a principal injector of energetic leptons into PWNe without
resorting to unrealistic properties for the shock layer turbulence or MHD
structure.Comment: 19 pages, 5 figures, invited review to appear in Proc. of the
inaugural ICREA Workshop on "The High-Energy Emission from Pulsars and their
Systems" (2010), eds. N. Rea and D. Torres, (Springer Astrophysics and Space
Science series
Adult Congenital Heart Disease Investigated with Cardiac Catheterization Over A 20-Year Period
BACKGROUND: Recent advances in diagnosis and treatment have increased the life expectancy of patients with congenital heart disease. METHODS: To investigate the prevalence of adult congenital heart disease (ACHD) in a large registry of patients over a 20-year period, we retrospectively assessed data of 14,012 males and 4,461 females who underwent clinically indicated cardiac catheterization from 1984 to 2003. RESULTS: ACHD was recorded in 234 subjects aged from 18 to 66 years, [95 males (40.7%) and 139 females (59.3%)]. Females were more likely to present with ACHD than males (p<0.001). Atrial septal defect was the most common defect (43.3%) followed by partial anomalous pulmonary venous return (12.0%), pulmonary valve stenosis (11.3%) ventricular septal defect (8.0%), coarctation of aorta (5.5%) patent ductus arteriosus (4.0%) and Fallot's tetralogy (3.3%). Atrial septal defect was more common in females (p<0.01), while pulmonary valve stenosis was more frequent in males (p<0.05). No difference across sexes was found in the other forms of ACHD. Females with ACHD were significantly older than males at the time of catheterization (median age 41 years, interquartile range 26 to 53 years vs. median age 35 years, interquartile range 22 to 48 years, p<0.05). CONCLUSIONS: In adulthood ACHD is found more commonly in females and is diagnosed later in life than in males. Atrial septal defect is the most prevalent form of ACHD and occurs most commonly in females
Measuring the closeness of relationships: a comprehensive evaluation of the 'Inclusion of the Other in the Self' scale
Understanding the nature and influence of social relationships is of increasing interest to behavioral economists, and behavioral scientists more generally. In turn, this creates a need for tractable, and reliable, tools for measuring fundamental aspects of social relationships. We provide a comprehensive evaluation of the 'Inclusion of the Other in the Self' (IOS) Scale, a handy pictorial tool for measuring the subjectively perceived closeness of a relationship. The tool is highly portable, very easy for subjects to understand and takes less than 1 minute to administer. Across our three online studies with a diverse adult population (n=772) we show that six different scales designed to measure relationship closeness are all highly significantly positively correlated with the IOS Scale. We then conduct a Principal Component Analysis to construct an Index of Relationship Closeness and find that it correlates very strongly (ρ=.85) with the IOS Scale. We conclude that the IOS Scale is a psychologically meaningful and highly reliable measure of the subjective closeness of relationships
Two Energy Scales and two Quasiparticle Dynamics in the Superconducting State of Underdoped Cuprates
The superconducting state of underdoped cuprates is often described in terms
of a single energy-scale, associated with the maximum of the (d-wave) gap.
Here, we report on electronic Raman scattering results, which show that the gap
function in the underdoped regime is characterized by two energy scales,
depending on doping in opposite manners. Their ratios to the maximum critical
temperature are found to be universal in cuprates. Our experimental results
also reveal two different quasiparticle dynamics in the underdoped
superconducting state, associated with two regions of momentum space: nodal
regions near the zeros of the superconducting gap and antinodal regions. While
antinodal quasiparticles quickly loose coherence as doping is reduced, coherent
nodal quasiparticles persist down to low doping levels. A theoretical analysis
using a new sum-rule allows us to relate the low-frequency-dependence of the
Raman response to the temperature-dependence of the superfluid density, both
controlled by nodal excitations.Comment: 16 pages, 5 figure
\u201cGive, but Give until It Hurts\u201d: The Modulatory Role of Trait Emotional Intelligence on the Motivation to Help
Two studies investigated the effect of trait Emotional Intelligence (trait EI) on people\u2019s moti- vation to help. In Study 1, we developed a new computer-based paradigm that tested partic- ipants\u2019 motivation to help by measuring their performance on a task in which they could gain a hypothetical amount of money to help children in need. Crucially, we manipulated partici- pants\u2019 perceived efficacy by informing them that they had been either able to save the chil- dren (positive feedback) or unable to save the children (negative feedback). We measured trait EI using the Trait Emotional Intelligence Questionnaire\u2013Short Form (TEIQue-SF) and assessed participants\u2019 affective reactions during the experiment using the PANAS-X. Results showed that high and low trait EI participants performed differently after the presen- tation of feedback on their ineffectiveness in helping others in need. Both groups showed increasing negative affective states during the experiment when the feedback was negative; however, high trait EI participants better managed their affective reactions, modulating the impact of their emotions on performance and maintaining a high level of motivation to help. In Study 2, we used a similar computerized task and tested a control situation to explore the effect of trait EI on participants\u2019 behavior when facing failure or success in a scenario unre- lated to helping others in need. No effect of feedback emerged on participants\u2019 emotional states in the second study. Taken together our results show that trait EI influences the impact of success and failure on behavior only in affect-rich situation like those in which people are asked to help others in need
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